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Run-Time Abstraction Services (RTAS) is run-time firmware that provides abstraction to the operating systems running on IBM System i and IBM System p computers.
It contrasts with Open Firmware, in that the latter is usually used only during boot, while RTAS is used during run-time.
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In computing, BIOS is firmware used to perform hardware initialization during the booting process, and to provide runtime services for operating systems and programs. The BIOS firmware comes pre-installed on a personal computer's system board, and it is the first software to run when powered on. The name originates from the Basic Input/Output System used in the CP/M operating system in 1975. The BIOS originally proprietary to the IBM PC has been reverse engineered by some companies looking to create compatible systems. The interface of that original system serves as a de facto standard.
In computing, a virtual machine (VM) is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination.
In computing, booting is the process of starting a computer. It can be initiated by hardware such as a button press, or by a software command. After it is switched on, a computer's central processing unit (CPU) has no software in its main memory, so some process must load software into memory before it can be executed. This may be done by hardware or firmware in the CPU, or by a separate processor in the computer system.
In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide hardware abstraction services to higher-level software such as operating systems. For less complex devices, firmware may act as the device's complete operating system, performing all control, monitoring and data manipulation functions. Typical examples of devices containing firmware are embedded systems, home and personal-use appliances, computers, and computer peripherals.
IBM PC compatible computers are similar to the original IBM PC, XT, and AT that are able to use the same software and expansion cards. Such computers were referred to as PC clones, or IBM clones. The term "IBM PC compatible" is now a historical description only, since IBM no longer sells personal computers. The designation "PC", as used in much of personal computer history has not meant "personal computer" generally, but rather an x86 computer capable of running the same software that a contemporary IBM PC could. The term was initially in contrast to the variety of home computer systems available in the early 1980s, such as the Apple II, TRS-80, and Commodore 64. Later, the term was primarily used in contrast to Apple's Macintosh computers.
System software is software designed to provide a platform for other software. Examples of system software include Operating Systems (OS) like macOS, Linux, Android and Microsoft Windows, computational science software, game engines, search engines, industrial automation, and software as a service applications.
Open Firmware is a standard defining the interfaces of a computer firmware system, formerly endorsed by the Institute of Electrical and Electronics Engineers (IEEE). It originated at Sun Microsystems, where it was known as OpenBoot, and has been used by vendors including Sun, Apple, IBM and ARM. Open Firmware allows the system to load platform-independent drivers directly from a PCI device, improving compatibility.
Hardware abstractions are sets of routines in software that provide programs with access to hardware resources through programming interfaces. The programming interface allows all devices in a particular class C of hardware devices to be accessed through identical interfaces even though C may contain different subclasses of devices that each provide a different hardware interface.
Common Hardware Reference Platform (CHRP) is a standard system architecture for PowerPC-based computer systems published jointly by IBM and Apple in 1995. Like its predecessor PReP, it was conceptualized as a design to allow various operating systems to run on an industry standard hardware platform, and specified the use of Open Firmware and RTAS for machine abstraction purposes. Unlike PReP, CHRP incorporated elements of the Power Macintosh architecture and was intended to support the classic Mac OS and NetWare, in addition to the four operating systems that had been ported to PReP at the time.
PowerPC Reference Platform (PReP) was a standard system architecture for PowerPC-based computer systems developed at the same time as the PowerPC processor architecture. Published by IBM in 1994, it allowed hardware vendors to build a machine that could run various operating systems, including Windows NT, OS/2, Solaris, Taligent and AIX.
The Unified Extensible Firmware Interface (UEFI) is a publicly available specification that defines a software interface between an operating system and platform firmware. UEFI replaces the legacy Basic Input/Output System (BIOS) firmware interface originally present in all IBM PC-compatible personal computers, with most UEFI firmware implementations providing support for legacy BIOS services. UEFI can support remote diagnostics and repair of computers, even with no operating system installed.
A hypervisor is a kind of emulator; it is computer software, firmware or hardware that creates and runs virtual machines. A computer on which a hypervisor runs one or more virtual machines is called a host machine, and each virtual machine is called a guest machine. The hypervisor presents the guest operating systems with a virtual operating platform and manages the execution of the guest operating systems. Multiple instances of a variety of operating systems may share the virtualized hardware resources: for example, Linux, Windows, and macOS instances can all run on a single physical x86 machine. This contrasts with operating-system–level virtualization, where all instances must share a single kernel, though the guest operating systems can differ in user space, such as different Linux distributions with the same kernel.
In Windows NT operating systems, the System Idle Process contains one or more kernel threads which run when no other runnable thread can be scheduled on a CPU. In a multiprocessor system, there is one idle thread associated with each CPU core. For a system with hyperthreading enabled, there is an idle thread for each logical processor.
Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to store BIOS settings. It is traditionally called CMOS RAM because it uses a volatile, low-power complementary metal-oxide-semiconductor (CMOS) SRAM powered by a small "CMOS" battery when system and standby power is off. It is referred to as non-volatile memory or NVRAM because, after the system loses power, it does retain state by virtue of the CMOS battery. The typical NVRAM capacity is 256 bytes.
A live USB is a USB flash drive or external hard disk drive containing a full operating system that can be booted. They are the evolutionary next step after live CDs, but with the added benefit of writable storage, allowing customizations to the booted operating system. Live USBs can be used in embedded systems for system administration, data recovery, or test driving, and can persistently save settings and install software packages on the USB device.
The RISC System/6000 (RS/6000) is a family of RISC-based Unix servers, workstations and supercomputers made by IBM in the 1990s. The RS/6000 family replaced the IBM RT PC computer platform in February 1990 and was the first computer line to see the use of IBM's POWER and PowerPC based microprocessors. In October 2000, the RS/6000 brand was retired for POWER-based servers and replaced by the eServer pSeries. Workstations continued under the RS/6000 brand until 2002, when new POWER-based workstations were released under the IntelliStation POWER brand.
Conversational Programming System or CPS was an early Time-sharing system offered by IBM which ran on System/360 mainframes circa 1967 through 1972 in a partition of OS/360 Release 17 MFT II or MVT or above. CPS was implemented as an interpreter, and users could select either a rudimentary form of BASIC or a reasonably complete version of PL/I. A third option provided remote job entry (RJE) features allowing users to submit JCL job streams for batch processing. A fourth option was called control mode. Normally, only the system operator would be permitted to use control mode. The available features in control mode included:
Linux startup process is the multi-stage initialization process performed during booting a Linux installation. It is in many ways similar to the BSD and other Unix-style boot processes, from which it derives.
Proprietary firmware is any firmware on which the producer has set restrictions on use, private modification, copying, or republishing.
RTAS may refer to: